Field of the Invention
The present invention relates to Dental Appliances methods for treating Obstructive Sleep Apnea and malocclusion correction.
Discussion of the Prior Art
Individuals with Obstructive Sleep Apnea (“OSA”) may have small, retruded chins and crowded lower teeth that cause the tongue to be pushed back against the airway, causing constriction of the airway, one of the primary causes of OSA. The obstruction in OSA is, more specifically, partial or complete obstruction of the upper airway during sleep. Sleep apnea causes drops in the blood oxygenation level and often adversely affects the heart by increasing blood pressure and pulse rate. Many aspects of a person's quality of life (e.g., physical and emotional health) are affected by OSA.
A typical approach for treating OSA is two-pronged, first, the patient is treated with traditional orthodontic appliances (e.g., braces) to expand the lower teeth at least partially and, second, the patient is fitted with a Mandibular Advancement Splint (MAS) appliance to move the lower jaw forward at night to lessen the patient's obstruction.
This two pronged approach is intended to lessen the severity of and treat the symptoms of OSA. An example of a Mandibular Advancement Splint (“MAS”) device is found in U.S. Pat. No. 6,604,527, which is incorporated by reference for the sole purpose of providing technical and anatomical nomenclature.
In the OSA patient, sagittal mandibular or lower jaw movement occurs within a range limited by the border movements, broadly characterized by the most protruded path of opening and closure, the maximal open position of the mandible, the occlusal positions and the most retruded path of closure. In this sense, a reference herein to mandibular advancement represents locating the mandible so that it functions in the protruded range from the reflex or habital path of closure (occurring between the intercuspal occlusal position and the maximum open position) to the protrusive border path. Treatments using the MAS dental appliance (e.g., 90, as shown in FIG. 1B) push the lower jaw forward, and this treatment essentially involves wearing an appliance with upper and lower segments that engage each other (e.g., upper and lower flanges 92, 94) when the mouth is closed and the lower jaw is pushed forward, opening the airway.
Another treatment for obstructive sleep apnea involves wearing and sleeping with a Continuous Positive Airway Pressure (CPAP) mask, which pushes pressurized air into the lungs to get past the obstruction. CPAP is a well-known therapy for treating sleep apnea. OSA patients wear a CPAP face or nasal mask during sleep. The mask, connected to a pump, provides a positive flow of air into the nasal passages in order to keep the airway open. The CPAP form of treatment is cumbersome, difficult, uncomfortable and disruptive for the bed partners.
Malocclusion is the misalignment of teeth and/or an incorrect relation between the teeth of the upper and lower dental arches, giving rise to faulty contact between upper and lower teeth. Sometimes skeletal disharmony of the face, and in particular an incorrect relationship between the maxilla and mandible, is a contributing factor or even the root cause of malocclusion. The MAS device and method for mandibular advancement described in U.S. Pat. No. 6,604,527 is not configured to correct malocclusion, which is why prior art methods may require simultaneous use of braces.
For patients who have no issues with OSA, orthodontic treatment for malocclusion can be addressed using traditional braces or “clear aligner” treatments such as those sold under the brand name Invisalign® by Align Technologies, Inc. Invisalign® appliances are typically provided in pairs (for upper and lower arches, e.g., 80, as shown in FIG. 1A) each configured as a thin concave trough of material that forms a receiving cavity geometry generally conforming to a patient's teeth but slightly out of alignment with the initial tooth configuration.
Clear aligner appliances are made using polymers such as thermoplastic polyurethane. Polymers may deform over time and use due to external and internal forces. Deformation causing external forces may include flexion from repeated insertions and removals and deformation from biting or wearing the aligners. An internal deforming force may include material stress relaxation. The deformation may reduce tooth moving forces, thereby reducing the usefulness of the dental appliance. Once the usefulness of the aligner dental appliance is reduced, the dental appliance is typically discarded, and either a replacement dental appliance is made or the next dental appliance in the treatment series is used.
Clear aligners are like retainers (or trays) that move teeth over a period of time to correct misalignments, such as crowding. A series of aligners are made to treat each specific case, ranging from 10-30 aligners for an average patient. Patients typically wear a new set of aligners (upper and lower) every two weeks for a period of time as needed to make the alignment correction for the teeth.
The treatment for malocclusion and the treatment for OSA are completely separate and distinct modalities. Patients are treated orthodontically to expand the lower arch by correcting crowding (permanently) and a completely separate MSA appliance (e.g., 90, as shown in FIG. 1B) is also fitted to move their jaw (temporarily, while they sleep) to help with their breathing.
These two treatments (wearing braces and wearing an MSA splint) are problematic for the patient, since wearing braces (or clear aligners) makes wearing an MSA splint appliance awkward for some and impossible for others. There is a need, therefore, for a convenient, flexible, effective and unobtrusive system and method for treating OSA while simultaneously correcting malocclusion which overcomes these problems.